1. Technical Field of the Invention
The present invention relates to a spout seal for combipacks. These are mainly intended for packs in the shape of such combipacks made of foil-coated paper containing liquids, for example milk, fruit juices, various kinds of non-alcoholic beverages or generally liquids also in the non-food sector. However, the seal may also be used for combipacks containing free-flowing goods such as sugar, semolina, or various kinds of chemicals. The foil-coated paper consists of a laminate material, for example of a paper or carton layer coated with a plastic material, for example polyethylene, and/or aluminum. The common volumes of such packs range from 20 cl up to 2 liters and more. A hole is punched out of the combipack at the position of the clearance opening of the seal to be fused on, which matches the clearance opening of the seal, which is subsequently sealed with a sealing foil.
2. Description of the Prior Art
There are various designs of spout seals made of plastic to be fused onto combipacks prepared in such a way. They form a bottom part, which is fused onto the combipack and a swivel lid piece attached thereto with a hinge. The bottom part has a circular lip that projects upwards around the clearance opening of the seal. This lip forms a spout at the front side of this bottom part. The lid hinged to the back of the bottom part has a downward-bulging shape. When the lid is closed, this fits into the inside of the lip of the bottom part and snaps into place there so that the spout is sealed. Upon first opening, and thus swinging the lid open for the first time, the sealing foil, which is located beneath the bottom part and covers the punched-out hole in the combipack, becomes visible on the inside of the upward-projecting lip of the bottom part. Outside the hole, the bottom part of the spout seal is fused onto the combipack with its plane bottom side. This means that, by default, the combipack is punched out in the place where the inside of the lip of the bottom part of the seal lies, and a sealing foil covers this section. The sealing foil may consist of an aluminum foil, which is glued together with the carton layer of the pack on the inside of the combipack. However, it may also consist of a PE coating, which is fused onto the inside of the carton material of the pack by means of high-frequency welding so that it covers the punched-out section onto which the spout seal is fused at a later stage. When the seal is opened for the first time by swinging its lid open, the sealing foil—an aluminum or a PE foil—becomes visible on the inside of the upward-projecting lip of the bottom part of the seal. The user then punches this foil in with a finger, which subsequently allows pouring out the content of the combipack through the spout formed by the protruding lip via its spout shape at the front.
The prior art includes European Patent Application No. 0,658,480 (Tetra Laval Holdings & Finance), which describes a seal having a small shoulder, at the bottom of the lid, which lifts an opening strip when the seal is swiveled open. The connection between this shoulder and the open strip then tears off and the opening strip, which seals the prepunched hole, can be manually torn off. This strip, however, has to be separately torn off and does not tear when the lid is swiveled open. French Patent No. 2,738,552 (Rical SA) shows a seal with a similar structure, whereby a sealing foil covers its clearance opening. This foil is part of the seal itself and is connected to it in one piece. When the lid is opened, this foil is torn out of the bottom part. Consequently, the lid does not tear out a sealing foil on the packaging material itself. Japan Patent Application 08-119265, Patent Abstracts of Japan, Vol. 1996, No. 09 (Shikoku Kakoki Co. Ltd.), discloses a seal similar to those in the above-mentioned prior art.
These conventional spout seals have several disadvantages. First of all, the pouring spout of the seals often does not have a very advantageous shape so that liquid runs down on the outside of the spout and down the combipack after pouring due to capillary effects. This spilling of the spout is very annoying, because often the entire front side of the combipack becomes soiled. In addition, another disadvantage of conventional solutions is that the seal has to be opened separately with a finger by pressing in the sealing foil after initially swinging the lid open. However, this method of opening the sealing foil is unhygienic. Moreover, the sealing foil is often not cleanly and entirely removed from the clear space inside the projecting lip. On the contrary, the sealing foil is torn open somewhere in its center section and then not properly pressed downwards into the inside of the combipack. This results in frayed edges on both sides, which protrude into the inside of the combipack and hamper and limit the free and clean flow of the content when pouring. If the combipack is tilted too much into the pouring direction, the mostly too small dimensions of the opening of the bottom part do not let enough air flow into the inside of the combipack. This leads to unwanted bubbling, meaning unsteady pouring in surges, which impedes targeted dosing into a glass or cup. In addition, the lid of many conventional seals is not reliably supported when the lid is open so that the lid slowly swings shut again due to material tension in the hinge section and hampers the pouring flow, unless one purposely keeps the lid part open with one hand, which is tedious. In many cases, one hand is needed to hold the combipack and pour while the other holds a glass, for example, into which the content is to be poured. This does not leave one hand free to hold the lid open. In addition, conventional spout seals have few user-friendly guarantee features, which are supposed to guarantee the initial opening, i.e. the initial swinging up of the seal top. With some solutions, a guarantee tape has to be tom off, which has to be grabbed with two fingers. This is often difficult in practice. For example, when the user has applied hand cream or sunscreen, it will be difficult for him to tear off the guarantee tape as long as his hands are greasy. Opening the seal with gloves is even less possible. And finally, re-closing is also not satisfactory because the seals are not sufficiently tight after closing the lid.